Primarily this research is intended to show in a uniform manner, the effect of various electrical parameters controlling and basic phenomena underlying augmentation of healing in an osteotomy when electric currents are applied. To reach this objective, parameters such as electrode current density, total potential and electrode material are being studied. Biochemical methods are currently being used to evaluate the effects. Electrochemical reactions of porous titanium are being evaluated in an in vitro situation. The biochemical consequences of applying electric current to bone are under study by investigating hydroxyproline and proline uptake, Ca45 uptake and cyclic AMP levels. However, the lack of repeatibility has hampered our progress in understanding the biochemical alterations occurring at the electrodes. The total number of animals stimulated has increased and as before a wide range of current densities has been found in which augmentation can occur at a cathode. As before, no specific preference for any frequency or modality has been observed. Studies of bone ingrowth into porous alumina and tricalcium phosphate are underway. Electrodes of porous titanium have been fabricated and will shortly be used experimentally in our animal model.